Re: [PATCH v2] rust: page: add byte-wise atomic memory copy methods

[Peter Zijlstra]

On Fri, Feb 13, 2026 at 08:19:17AM -0800, Boqun Feng wrote:
> Well, in standard C, technically memcpy() has the same problem as Rust's
> `core::ptr::copy()` and `core::ptr::copy_nonoverlapping()`, i.e. they
> are vulnerable to data races. Our in-kernel memcpy() on the other hand
> doesn't have this problem. Why? Because it's volatile byte-wise atomic
> per the implementation.

Look at arch/x86/lib/memcpy_64.S, plenty of movq variants there. Not
byte-wise. Also, not a single atomic operation in sight.